"""
Piper TTS HTTP service.
Self-hosted text-to-speech, internal network only.
"""
import io
import logging
import os
import wave
from contextlib import asynccontextmanager

from fastapi import FastAPI, HTTPException
from fastapi.responses import Response
from pydantic import BaseModel
import piper

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

MODEL_PATH = os.getenv("PIPER_MODEL", "/app/models/en_US-lessac-medium.onnx")
voice = None


@asynccontextmanager
async def lifespan(app: FastAPI):
    global voice
    logger.info(f"Loading Piper model: {MODEL_PATH}")
    voice = piper.PiperVoice.load(MODEL_PATH)
    logger.info("Piper TTS ready.")
    yield
    logger.info("Shutting down.")


app = FastAPI(title="Piper TTS Service", lifespan=lifespan)


class TTSRequest(BaseModel):
    text: str
    speaker_id: int = None
    length_scale: float = 1.0
    sentence_silence: float = 0.2


@app.get("/health")
async def health():
    if voice is None:
        raise HTTPException(status_code=503, detail="Model not loaded")
    return {"status": "ok", "model": os.path.basename(MODEL_PATH)}


@app.post("/synthesize")
async def synthesize(req: TTSRequest):
    if voice is None:
        raise HTTPException(status_code=503, detail="Model not loaded")

    if not req.text.strip():
        raise HTTPException(status_code=400, detail="Empty text")

    buf = io.BytesIO()
    with wave.open(buf, "wb") as wf:
        synth_kwargs = {
            "length_scale": req.length_scale,
            "sentence_silence": req.sentence_silence,
        }
        if req.speaker_id is not None:
            synth_kwargs["speaker_id"] = req.speaker_id
        voice.synthesize(req.text, wf, **synth_kwargs)

    return Response(
        content=buf.getvalue(),
        media_type="audio/wav",
        headers={"Content-Disposition": "inline; filename=speech.wav"},
    )